CVE-2021-25660 : What You Need to Know

A vulnerability has been identified in multiple Siemens products including SIMATIC HMI Comfort Panels and SIMATIC WinCC Runtime Advanced. The vulnerability in SmartVNC could lead to a Denial-of-Service condition when triggered on the server side by client data.

Understanding CVE-2021-25660

This CVE refers to an out-of-bounds memory access vulnerability in Siemens products, potentially causing a Denial-of-Service situation.

What is CVE-2021-25660?

The vulnerability affects SIMATIC HMI Comfort Outdoor Panels V15 & V16, SIMATIC HMI Comfort Panels V15 & V16, SIMATIC HMI KTP Mobile Panels V15 & V16, and SIMATIC WinCC Runtime Advanced V15 & V16.

The Impact of CVE-2021-25660

Exploitation of this vulnerability could lead to a Denial-of-Service condition, impacting the availability of the affected products and systems.

Technical Details of CVE-2021-25660

The vulnerability, categorized as CWE-788: Access of Memory Location After End of Buffer, allows an unauthorized user to access memory beyond the allocated buffer space.

Vulnerability Description

The SmartVNC component in the affected Siemens products allows for the out-of-bounds memory access, potentially causing system disruption.

Affected Systems and Versions

All versions of the specified products below the indicated update levels are vulnerable:

SIMATIC HMI Comfort Outdoor Panels V15 & V16
SIMATIC HMI Comfort Panels V15 & V16
SIMATIC HMI KTP Mobile Panels V15 & V16
SIMATIC WinCC Runtime Advanced V15 & V16

Exploitation Mechanism

The vulnerability can be triggered on the server side by sending specific data from the client, exploiting the out-of-bounds memory access capability.

Mitigation and Prevention

To address CVE-2021-25660, immediate steps and long-term security practices should be followed alongside timely patching and updates.

Immediate Steps to Take

Apply security updates provided by Siemens to mitigate the vulnerability.
Restrict network access to the affected products to reduce exposure.

Long-Term Security Practices

Regularly monitor and apply security patches to ensure system integrity.
Implement network segmentation and access controls to limit unauthorized access.

Patching and Updates

Ensure timely installation of the latest updates released by Siemens to patch the vulnerability and enhance system security.